view mercurial/statichttprepo.py @ 22196:23fe278bde43

largefiles: keep largefiles from colliding with normal one during linear merge

Before this patch, linear merging of modified or newly added largefile
causes unexpected result, if (1) largefile collides with same name
normal one in the target revision and (2) "local" largefile is chosen,
even though branch merging between such revisions doesn't.

Expected result of such linear merging is:

  (1) (not yet recorded) largefile is kept in the working directory
  (2) largefile is marked as (re-)"added"
  (3) colliding normal file is marked as "removed"

But actual result is:

  (1) largefile in the working directory is unlinked
  (2) largefile is marked as "normal" (so treated as "missing")
  (3) the dirstate entry for colliding normal file is just dropped

(1) is very serious, because there is no way to restore temporarily
modified largefiles.

(3) prevents the next commit from adding the manifest with correct
"removal of (normal) file" information for newly created changeset.

The root cause of this problem is putting "lfile" into "actions['r']"
in linear-merging case. At liner merging, "actions['r']" causes:

  - unlinking "target file" in the working directory, but "lfile" as
    "target file" is also largefile itself in this case

  - dropping the dirstate entry for target file

"actions['f']" (= "forget") does only the latter, and this is reason
why this patch doesn't choose putting "lfile" into it instead of
"actions['r']".

This patch newly introduces action "lfmr" (LargeFiles: Mark as
Removed) to mark colliding normal file as "removed" without unlinking
it.

This patch uses "hg debugdirstate" instead of "hg status" in test,
because:

  - choosing "local largefile" hides "removed" status of "remote
    normal file" in "hg status" output, and

  - "hg status" for "large2" in this case has another problem fixed in
    the subsequent patch

# statichttprepo.py - simple http repository class for mercurial
#
# This provides read-only repo access to repositories exported via static http
#
# Copyright 2005-2007 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from i18n import _
import changelog, byterange, url, error
import localrepo, manifest, util, scmutil, store
import urllib, urllib2, errno, os

class httprangereader(object):
    def __init__(self, url, opener):
        # we assume opener has HTTPRangeHandler
        self.url = url
        self.pos = 0
        self.opener = opener
        self.name = url
    def seek(self, pos):
        self.pos = pos
    def read(self, bytes=None):
        req = urllib2.Request(self.url)
        end = ''
        if bytes:
            end = self.pos + bytes - 1
        if self.pos or end:
            req.add_header('Range', 'bytes=%d-%s' % (self.pos, end))

        try:
            f = self.opener.open(req)
            data = f.read()
            # Python 2.6+ defines a getcode() function, and 2.4 and
            # 2.5 appear to always have an undocumented code attribute
            # set. If we can't read either of those, fall back to 206
            # and hope for the best.
            code = getattr(f, 'getcode', lambda : getattr(f, 'code', 206))()
        except urllib2.HTTPError, inst:
            num = inst.code == 404 and errno.ENOENT or None
            raise IOError(num, inst)
        except urllib2.URLError, inst:
            raise IOError(None, inst.reason[1])

        if code == 200:
            # HTTPRangeHandler does nothing if remote does not support
            # Range headers and returns the full entity. Let's slice it.
            if bytes:
                data = data[self.pos:self.pos + bytes]
            else:
                data = data[self.pos:]
        elif bytes:
            data = data[:bytes]
        self.pos += len(data)
        return data
    def readlines(self):
        return self.read().splitlines(True)
    def __iter__(self):
        return iter(self.readlines())
    def close(self):
        pass

def build_opener(ui, authinfo):
    # urllib cannot handle URLs with embedded user or passwd
    urlopener = url.opener(ui, authinfo)
    urlopener.add_handler(byterange.HTTPRangeHandler())

    class statichttpvfs(scmutil.abstractvfs):
        def __init__(self, base):
            self.base = base

        def __call__(self, path, mode="r", atomictemp=None):
            if mode not in ('r', 'rb'):
                raise IOError('Permission denied')
            f = "/".join((self.base, urllib.quote(path)))
            return httprangereader(f, urlopener)

        def join(self, path):
            if path:
                return os.path.join(self.base, path)
            else:
                return self.base

    return statichttpvfs

class statichttppeer(localrepo.localpeer):
    def local(self):
        return None
    def canpush(self):
        return False

class statichttprepository(localrepo.localrepository):
    supported = localrepo.localrepository._basesupported

    def __init__(self, ui, path):
        self._url = path
        self.ui = ui

        self.root = path
        u = util.url(path.rstrip('/') + "/.hg")
        self.path, authinfo = u.authinfo()

        opener = build_opener(ui, authinfo)
        self.opener = opener(self.path)
        self.vfs = self.opener
        self._phasedefaults = []

        try:
            requirements = scmutil.readrequires(self.opener, self.supported)
        except IOError, inst:
            if inst.errno != errno.ENOENT:
                raise
            requirements = set()

            # check if it is a non-empty old-style repository
            try:
                fp = self.opener("00changelog.i")
                fp.read(1)
                fp.close()
            except IOError, inst:
                if inst.errno != errno.ENOENT:
                    raise
                # we do not care about empty old-style repositories here
                msg = _("'%s' does not appear to be an hg repository") % path
                raise error.RepoError(msg)

        # setup store
        self.store = store.store(requirements, self.path, opener)
        self.spath = self.store.path
        self.sopener = self.store.opener
        self.svfs = self.sopener
        self.sjoin = self.store.join
        self._filecache = {}
        self.requirements = requirements

        self.manifest = manifest.manifest(self.sopener)
        self.changelog = changelog.changelog(self.sopener)
        self._tags = None
        self.nodetagscache = None
        self._branchcaches = {}
        self.encodepats = None
        self.decodepats = None

    def _restrictcapabilities(self, caps):
        caps = super(statichttprepository, self)._restrictcapabilities(caps)
        return caps.difference(["pushkey"])

    def url(self):
        return self._url

    def local(self):
        return False

    def peer(self):
        return statichttppeer(self)

    def lock(self, wait=True):
        raise util.Abort(_('cannot lock static-http repository'))

def instance(ui, path, create):
    if create:
        raise util.Abort(_('cannot create new static-http repository'))
    return statichttprepository(ui, path[7:])